Method of producing slide-fastener stringers

ABSTRACT

A slide-fastener stringer, especially a slide-fastener stringer half, is formed by stitching individually the turns of an endless coupling element to a support tape with a chain stitch, each stitch being produced as each turn of the coupling element is formed. The chain stitches may secure the shanks of the coupling members to the tape and may lie wholly shielded by shanks which are not engaged by the stitches.

United States Patent 91 Heimberger et a1.

[ 1] 3,728,979 1 Apt 24,1973

[ METHOD OF PRODUCING SLIDE- FASTENER STRINGERS [75] Inventors: Helmut Heimberger, D7887 Grenzach; Karl Griesbaum, 43

Essen-Steele, both of Germany [73] Assignee: Opti-Holding AG, Glarus, Switzerland [22] Filed: Nov. 27, 1970 [21] Appl. N0.: 93,273

[30] Foreign Application Priority Data Nov. 28, 1969 Germany ..P 19 59 886.8

[52] US. Cl. ..112/265 [51] Int. Cl. .....D05b 3/12, DOSb 97/10, DOSb 97/12 [58] Field of Search ..112/105,265,158, 112/162; 24/205.16 R, 205.16 C, 201 C,

[56] References Cited UNITED STATES PATENTS 3,507,031 10/1962 Wahl ..24/205.16 C

3,474,505 10/1969 Glindmeyer ..24/205.13 C X 3,600,767 8/1971 Cowdrey et a1. ..24/205.16 3,038,207 6/1962 Schwartz .,l 12/105 X 3,176,637 4/1965 MacFee ..112/105 3,5 88,967 6/1971 Speck 24/205.16 C

3,316,870 5/1967 Burbank ..112/265 3,147,529 9/1964 Wilekeu 24/205.16 C 3,054,171 9/1962 Ruhrmann et a1. ..29/410 3,490,110 1/1970 Frolich ..1 12/265 X 3,376,837 4/1968 Nicolay ..112/158 R Primary Examiner-G. V. Larkin An0rneyl(arl F Ross [57] ABSTRACT A slide-fastener stringer, especially a slide-fastener stringer half, is formed by stitching individually the turns of an endless coupling element to a support tape with a chain stitch, each stitch being produced as each turn of the coupling element is formed. The chain stitches may secure the shanks of the coupling members to the tape and may lie wholly shielded by shanks which are not engaged by the stitches.

4 Claims, 15 Drawing Figures .PATENTEUAFRZMQTE 3.728.979

SHEET 1 [1F 6 v j Helmuf Heimberger l- I INVENTORSI Y BY Karl Griesbaum I.

Attorney PATENTEUAFRZMQYS 3-728;979

'SHEETEUFG I Helmuf Heimberger Karl Griesbaum INVENTORS.

BY (R955 Attorney PAIENTIEDAPR 24 I975 1 sum 3 OF 5 INVENTORS: He/muf- Heimberger BY I Karl Griesbaum Attorney PATENTEDAPR 24 an f I SHEET. u of 5 08 0. FIG. /0

i Helmuf Heimberg Karl Griesbaum INVENTORS;

Attorney PAI N EUAPM ms 7 .SHEET s 035 Helfnuf Heimb erger Karl Griesbaum I NVENTORS.

Attorney SHEET 8 BF 6 Helmuf Heimberger Karl Griesbau 1 Inventors.

' R af v Attorney METHOD OF PRODUCING SLIDE-FASTENER STRINGERS CROSS REFERENCE TO RELATED APPLICATION This application discloses subject matter which is re lated to the subject matter disclosed in the commonly assigned copending application Ser. No. 93,188 now US. Pat. No. 3,665,561, filed concurrently herewith by Helmut HEIMBERGER, one of the present joint inventors, and entitles SLlDE-FASTENER FORMED SIMULTANEOUSLY WITH ATTACHMENT TO SUPPORT TAPE.

FIELD OF THE INVENTION Our present invention relates to a method of and an apparatus for the production of slide fasteners and, more particularly, to improvements in the production of a slide-fastener stringer half with continuous coupling elements.

BACKGROUND OF THE INVENTION Slide fasteners have been provided heretofore with support tapes upon which are mounted respective rows of coupling members which are mutually engageable and disengageable upon the movement of a slider therealong. For the purposes of this disclosure, a stringer will be a slide-fastener assembly consisting of a pair of support tapes, each of which has a continuous coupling element along its edge confronting the edge of the other support tape; the coupling elements may be a meander or a coil of a synthetic resin monofilament and will generally have a plurality of closely spaced heads engageable behind the heads of the mating coupling element. In addition, the stringer is provided with some means for attaching each coupling element to the support tape, endstop members at each extremity of the coupling elements and/or plug-and-socket members in the case of a separable slide fastener. The stringer includes, as well, a slider adapted to be shifted along the coupling elements to matingly engage or disengage the coupling elements.

The term coupling element is used herein to define coils or meanders provided with closely spaced coupling heads which may have protuberances, projections, flanges or formations adapted to engage between the coupling heads of the opposed element and produced, for example, from a continuous synthetic resin monofilament, e-.g. a thermoplastic such as a polyamide (nylon) or polyester. The term stringer half" will refer to that portion of the assembly which comprises a single support tape, layer or band, the coupling element and the means for affixing the coupling element to the support.

The support tapes or bands of prior-art slide-fastener stringers have been composed of synthetic-resin foils or of fabric and may be knitted or woven. Furthermore, various forms of attachment have been used heretofore to affix each coupling element along the edge of the respective support tape. For example knitted support tapes may have had the coupling elements incorporated into the fabric by the knitting of loops therearound. Alternatively, openings may be provided in the fabric into which the heads of the coupling element are inserted. Woven support tapes may likewise be provided with openings, may include the coupling element as a warp thread while providing weft threads in engagement with the bights interconnecting the coupling heads of the particular element, etc.

Most frequently, however, the coupling elements have been secured to the support tapes by rows of stitching, namely chain stitching which passes over each turn or meander of the coupling element and may, if desired, form a guide bead for the slider. Such systems have the disadvantage that the movement of the slider back and forth along the rows of stitching securing the two coupling elements to the respective support tapes causes wear of the stitches which affix each coupling member to the support tape and produces eventual deterioration of the stringer. Furthermore, since the rows of stitching are exposed, they are subject to breakage and, indeed, the deterioration of the system by which the coupling elements are secured to the support tape, is a prime cause of breakdown of the slide fastener.

We may also mention the fact that filler cords have been provided within the coupling elements, especially where coils are employed, to support the turns of the coupling element against compressive stresses and to assist in securing the coupling element to the support tape, while maintaining the configuration and especially the gauge of the coupling heads. In many cases, the stitching also passes through this cord. Also, the stitching securing a coupling element to the support tape may include stitch loops which pass through a cord lying alongside that coupling element (i.e. along a flank thereof opposite the coupling heads) and engaging loops of the meander or coil from which the coupling element is constituted.

Systems in which the coupling element is woven or knitted into the support tape are highly expensive and difficult to control, whereas prior-art arrangements for stitching the coupling element to the support tape have the difficulties enumerated above. The stitching has the advantage that it can be relatively fine, thereby insuring a relatively close spacing of the coupling heads of the elements as is desirable in so-called invisible slide fasteners and wherever a no-snag high-quality closure is required. However, it has been found that the loops of the stitches which engage the turns of the coupling elements and especially those shanks of the coupling members which are spaced from the support tape, have a tendency to slide rearwardly over the bight of the loops of the coupling element and loosen, while those stitches which overlie the coupling element are subject to wear as indicated earlier. As a result, the conventional methods of affixing continuous coupling ele ments to support tapes in slide-fastener stringers have defects which could not be eliminated in spite of considerable effort in the art.

Mention may also be made of the various prior-art systems principally used for securing the coupling element to the support tape and in manufacturing the stringer. For the most part, the coupling element is coiled or formed from the continuous monofilament upon a mandrel or forming drum and the resulting coils or meanders are then fastened to the support tape by stitching or one of the other systems previously described. The handling of such coils or meanders is, of course, complex and expensive and it is frequently difficult to coordinate the feed of the coil with the stitching arrangement. Consequently, a two-step process has been used heretofore involving, firstly, the formation of the coil and, secondly, the mounting of the coil upon the support tape. It is interesting to note that one of the other difficulties of prior-art arrangements for producing slide-fastener stringers, is the fact that it is difficult accurately to wind coils of a monofilament with a relatively small diameter and close spacing and, on the other hand, it is difficult to sew coupling elements with such close head spacing to the fabric tape without deforming or distorting the coupling element.

OBJECTS OF THE INVENTION It is the principal object of the present invention to provide a method of producing an improved slidefastener stringer of stringer half.

It is another object of the invention to provide an improved method of making a slide-fastener stringer or stringer half which avoids the disadvantages of earlier techniques as noted above.

It is also an object of this invention to provide a system for the economical, convenient and rapid manufacture of a slide-fastener stringer whereby the aforementioned disadvantages are eliminated.

It is also an object of the invention to provide an im proved method of producing slide fasteners utilizing continuous coupling elements, namely, coils or meanders of monofilament synthetic resin to provide a more secure attachment of the coupling element to the support tape.

The invention has as its object also the provision of a method of making a slide fastener, which economically yields an improved slide fastener stringer which will not manifest loosening of the attachment of the coupling element upon breakage of a small number of attachment loops or of the attachment thread.

It is an object of the invention to provide a method of producing a slide fastener of the character described in which movement of the slider along the coupling element cannot wear away the attachment stitches.

SUMMARY OF THE INVENTION These objects and others which will become apparent hereinafter are attained, in accordance with the present invention, with a method of and an apparatus for the production of a slide-fastener stringer and, more particularly, a stringer half, which makes use of a chain-stitch sewing machine and the formation of each turn or undulation of the coupling coil or meander in step with the fastening or attachment of this turn to the support table. While earlier systems in the production of slide-fastener stringers have utilized the chain-stitch sewing machine, it has been for the purpose of fastening the preformed coupling element to the support tape.

When reference is made herein to a chain-stitch sewing machine, it should be understood that we intend to identify by this term a sewing machine which comprises the usual sewing or work table and stitch plate,-a needle reciprocable through this plate and perpendicularly thereto while having an eye through which an attachment thread is paid out, a transport mechanism for advancing the support tape stepwise in synchronism with the motion of the needle and in a direction transverse to the direction of reciprocation thereof, and loop-forming means along the side of the table opposite that at which the needle is reciprocably mounted for engaging the thread carried through the fabric by the needle, retaining a loop of this thread and drawing this loop along the fabric for engagement by the needle during its next thrust through the fabric.

For the most part, such machines comprise a main shaft which may be driven by a motor and connected by gear drives, chains and the like with the transport teeth and a cam arrangement for reciprocating the needle and shifting the loop-forming finger or loop retainer so that each loop is engaged by the finger when the needle passes through the fabric but is released on the next pass of the needle through the previously formed loop.

A chain stitch is therefore characterized by the presence on at least one side of the fabric of a chain of loops, each of which passes through the preceding loop and, in turn, anchors the succeeding loop or is anchored by a gripper thread. In a single-thread chain stitch and chain stitches formed by a single-needle chain-stitching machine, a single strand forms each stitch on the opposite side of the fabric whereas each loop stitch is constituted as a double strand.

According to an important feature of the present invention, the synthetic-resin monofilament adapted to constitute the coupling element is, in the rhythm of stitching of the chain-stitch sewing machine, carried alternately to and fro across the row of stitching to deposit on the first pass a shank which is engaged by the drawn-out loop retained by the loop former; on the next pass, the synthetic-resin monofilament may be carried over the rows of chain stitching to form a shank which overlies the affixed shank and thereby shield the row of stitching against deterioration by movement of the slider along the coupling elements.

According to another feature of the invention, retaining means is provided to operate in the cadence of the stitch formation and the coupling turn formation for engaging the head portion and the bight portion of each turn as the monofilament is carried to and fro across the stitching path. Such retaining means may be a mandrel which is periodically inserted into the path of the arm swinging the monofilament across the stitch path and is periodically withdrawn for the formation of the shank in contact with the support tape. Preferably, however, the retaining means includes a pair of fingers respectively forming the coupling head and the bight of each turn. It will be apparent from the foregoing discussion that the coupling turns or members are formed step by step in the cadence of the formation of each stitch, that each stitch engages the monofilament as it is laid across the path of the row of stitching by the thread loop previously described and is affixed concurrently with the formation of the member and that each stitch partly overlies at least one shank of each turn of the coupling element as it is formed while passing through the interior of the coupling element.

When we refer to the stitches of the chain-stitch sewing machine, in the absence of words indicating that a single-thread chain stitch is intended, we include the stitches of attachment rows which can utilize two or more threads and can be formed by two or more nee dles.

Still another feature of the invention resides in the embossment, impressment or deformation of the synthetic-resin monofilament at spaced-apart locations in the cadence of stitch formation at locations corresponding to the position of the coupling head to be formed upon the swinging of the synthetic-resin monofilament across the row of stitching. When, for example, the synthetic-resin monofilament is deformed by compression to produce lateral protuberances and the monofilament is bent or kinked at the head as the latter is formed, the protuberances constitute projections extending transversely of each coupling turn but in the longitudinal direction of the coupling element for engagement behind the similar projections of a mating coupling element upon engagement of two similarly produced slide-fastener halves. While we prefer to form the protuberances concurrently with the stitching and head-forming operation, we have found that it is also possible to make use of preformed monofilament, e.g. monofilament which has been pre-embossed at locations designed to form the coupling heads.

Furthermore, the principles of the present invention are applicable to the formation of classical slidefastener stringers in which the coupling element, as it is formed step by step from the synthetic-resin monofilament, is fastened by a double-chain stitch of the twothread type wherein the loops are secured by a further (gripper) thread engaging them. This further thread can constitute a cover thread which overlies the coupling members.

In other words, the principles of the present invention are applicable to the stitching of coupling elements (as they are formed) to support tapes with rows of stitching which pass over the outer shank of each turn of the coupling element and then between the coupling element in the form ofa double-chain stitch. However, we prefer to use the system of the instant invention to produce slide-fastener stringers of the type described in the above-mentioned copending application.

The slide-fastener stringer of the latter application comprises a pair of support tapes and a respective continuous coupling element lying along an edge of the support tape and so arranged and constructed that each coupling head of the continuous coupling element is associated with at least one shank which lies against the support tape while the attachment stitches pass only over these shanks. Hence, the means for attaching the coupling element to the support tape includes a row of chain stitches with each loop thereof engaging and partly surrounding each of the shanks resting upon the support tape and connected to the tape on opposite sides of these shanks, the loops lying within the coil space. Each coupling element provides shank portions of its turns or meanders which lie above the shank portions seized by the aforementioned thread loops to define the interior of the coil or meander through which the thread of the chain stitching passes. No threads of the chain stitching lie above the portions of the coupling elements most distal from the support tape. Hence a novel coupling element and stringer is provided.

It will be apparent that the system last described has the advantage that the chain stitching also constitutes a filler cord" which supports the coupling coil against compression, although we may provide an additional cord which is fed into the coupling members as they are formed.

Still another feature of this invention resides in the step of compressing the outer shanks of the coupling elements against the loops of chain stitching within each coupling member to clamp the chain stitches and thereby increase the security of the assembly against withdrawal of the stitches. The compressed shanks can be thermally welded to the underlying shanks and the entire assembly can be set by thermal techniques, e.g. the use of ultrasonic transducers. It is possible to employ a singlethread chain stitch which, by virtue of the welding mentioned earlier, is anchored to each turn of the coupling element and cannot be withdrawn.

Among the advantages of the present system is the fact that it provides for the manufacture of slidefastener stringers in a single operation, i.e. in the joint production of the coupling element and its attachment to the support tape rather than a two-step operation in which the coupling element is preformed.

Furthermore, it enables the use of a chain-stitch sewing machine with minor modifications utilizing, for example, the fabric-transport mechanism, the sewing mechanism and other parts of the apparatus without modification. The means for swinging the monofilament from side to side in a meander or a coil can simply be an arm coupled by a cam drive to the main drive unit of the sewing machine and provided with an eye through which the filament extends. The arm may accommodate monofilaments of a wide variety of sizes and cross-sections and, indeed, separate support bands need not be employed. Hence, whenever the term support tape is used herein, it should be assumed that the words apply to any fabric or sheet-like support structure serving the function of the usual support band of a slide-fastener stringer; using the system of the instant invention, therefore, the coupling coil may be applied directly to the fabric of a garment or the like. Furthermore, the usual support tape may be provided and the system used to simultaneously secure the coupling element to the support tape and the support tape to an overlying fabric or garment. The equipment cost for carrying out the present invention is thereby minimized.

DESCRIPTION OF THE DRAWING The above other objects, features and advantages of the present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. I is a perspective view,-partly in diagrammatic form, of a chain-stitch sewing machine modified to carry out the method of the present invention;

FIG. 2 is a view in the direction of arrow II of FIG. 1, illustrating a detail of the present invention during one phase of the loop-forming operation;

FIG. 3 is a view in the direction of arrow III showing the position of the parts corresponding to FIG. 2;

FIGS. 4 and 5 are views similar to FIGS. 2 and 3, respectively, illustrating the position of the various parts subsequent to withdrawal of the needle through the fabric;

FIGS. 6 and 7 are views similar to FIGS. 2 and 3, respectively, illustrating the operation of the transport elements and the relationship thereof to the retaining fingers;

FIGS. 8 and 9 are views generally similar to FIGS.2 and 3, respectively, but illustrating other positions of the several parts;

FIG. 10 is a detail view corresponding generally to FIG. 3 but illustrating a modification of the apparatus;

FIGS. 11 and 12 are views corresponding generally to FIGS. 3 and 7 but drawn to an enlarged scale and showing the incorporation of a separate filler cord in the body of the coil;

FIG. 13 represents a further modification of the system of FIG. 1 wherein the orientation of the filament-swinging arm is reversed;

FIG. 14 is a view similar to FIG. 1, showing the principles of the present invention in greater detail; and

FIG. 15 is a cross-sectional view taken generally along the line of XV XV of FIG. 14.

SPECIFIC DESCRIPTION In FIG. 1, we show only those portions of a general stitch-sewing machine which are relevant to the present invention. We have already pointed out that the means for reciprocating the needle, the means for displacing the loop former in synchronism with the needle, the means for transporting the workpiece for the fabric, and the worktable at which all of these elements cooperate, are conventional. An appropriate mechanism for co-ordinating the needle reciprocation with the transport mechanism and the movement of a loopforming finger is disclosed is US. Pat. No. 3,376,837 and the references therein cited.

To the transport mechanism of this conventional chain-stitch sewing machine is connected an upper transport comb 1 and a lower transport comb 2, the teeth of which engage between the coupling members 14 which are to be formed from the synthetic-resin monofilament 13. The main shaft of the chain-stitch sewing machine is provided with a conventional cam or eccentric drive which is applied via a shaft 9 to a swinging lever 3 of C or caliper configuration. The lever 3 has an arm 11 which rises below the fabric or support tape and the stitch plate or worktable 8, extending over the row of stitching 22 to be produced, and terminates in an eye 12 through which the synthetic-resin monofilament extends. The arm or lever 3, 11 swings about an axis A, defined by the shaft 9 and parallel to the direction of advance 7 of the fabric.

The cresent lever 3 is synchronized with a pair of retaining fingers 4, 5 constituted as a head retainer 4 and a bight retainer respectively. The retaining fingers 4,5, moreover, are connected to a drive 6, e.g. a cam and cam follower arrangement, operatively connected with the lever 3 so that the movement of the retainers 4, 5 is synchronized or triggered by the movement of the lever 3. v

Whereas the system of FIG. 1 forms each coupling member as it is secured to the tape 20, it is also possible to feed a filler cord 15, e.g. of textile, into the space within the coupling coil 14. This is illustrated in FIGS. 11 and 12 from which it is apparent that a disk 16 is provided in the eye of the lever 3 and is formed with an opening 18 through which the filler cord 15 is guided into the interior of the coupling coil while an opening 17 guides the monofilament 13 into the latter. The disk 16 is rotatable as represented at 19 about an axis eccentric to the openings 17 and 18. Consequently, as the lever 3 swings to carry the eye through about 180 (FIGS. 11 and 12), the filament remains on the outside while the tiller coil is fed to the interior of the coil. The machine otherwise is similar to that shown in FIG. 1

and the chain-stitch formation may be identical. In addition, the filler-cord arrangement in FIGS. 11 and 12 may be used in the machine of FIGS. 13 and 14 as required.

It will be appreciated that, in place of retaining members as shown at 4 and 5, for example, it is also possible to form the coupling element turn by turn using the mandrel. In this case, the mandrel is inserted for the formation of each turn and is withdrawn as the chain stitch is drawn over the previously formed coupling member shank. A mandrel arrangement of this type is fully illustrated in the aforementioned copending application. Similarly, the lever 3 and the retainers may be so constructed and arranged as to form a meander rather than a coupling coil of the type illustrated. The apparatus can be doubled so that to adjoining slide fastener halves can be made in one pass and, of course, the attachment can be carried out with several needles and with a multithread chain stitch. We have already noted that the fabric base 20 can be a support tape as has been illustrated in FIGS. 1 13 or the edge ofa garment, as shown in FIG. 13, the edge having a hem or an in-turned edge.

In FIG. 1 and where otherwise appropriate, the needle N has an eye B through which the thread T of the chain stitch passes. The needle is vertically reciprocated by the main drive mechanism as shown by the arrow B and, in the embodiment of FIG. 1, may pass through the fabric 20 from below. Above the fabric 20 is provided a loop-forming finger L which retains the loop formed by the needle and may supply a further thread C to the loop where a double-thread or double-chain stitch is to be formed. The loop retainer L is of course operated by the main drive mechanism. For convenience, the coupling element 14 may be conceived as comprising a head 14a with a pair of lateral protuberances 14b and engageable behind the corresponding protuberances of the heads of a mating coupling element. Extending rearwardly from each head 14a is an upper shank 14d and a lower shank 142,

the latter resting against the support fabric 20. The

shank 14e is connected to the preceding turn by one bight while each shank 14d is connected to the shank 142 of the succeeding turn by another bight 14q as best seen in FIG. 3. In general, therefore, the finger 5 engages the rearwardly shifted monofilament to permit the monofilament to be brought again to the right (FIG. 1) in the formation of a bight, while the finger 4 engages the monofilament to permit kinking of it as the head 14a is formed.

As is best seen in FIGS. 2 and 3, for example, the transport combs initially engage the previously formed element 14 and maintain it immobile while the needle N is thrust upwardly through the fabric and co-ordinates with the loop-forming finger L to produce a loop. For convenience, a separate cover thread has not been illustrated in the system of FIGS. 2 9 to avoid confusion. A loop L is thereby formed in the thread T (FIG. 2) and remains in place as the needle is withdrawn (FIGS. 4 and 5). The transport combs 1 and 2 further retain the coupling elements while the upper shank 14d is stretched by the arm 3 across the path of the stitch row (FIG. whereupon the combs 1 and 2 shift the assembly in the direction of arrow 7 (FIG. 1), disengage and re-engage the coupling element at the newly formed loop. The loop L is thereupon stretched across the coupling member and is engaged by the needle N at its next thrust upwardly through the fabric adjacent the newly formed coupling member but inwardly of the subsequently deposited lower shank (see FIG. 1). This movement of the needle forms a loop 1 within the loop 1 and the sequence is repeated with stretchin of the loop over the coupling member, etc.

From FIG. 1, it is also apparent that the finger 4 may serve to plastically deform the monofilament 13 at 23 to produce the lateral protuberances defining the coupling head, the monofilament being kinked in this region during the subsequent rearward pass of the lever 3. However, it has been found to be advantageous to provide two such embossing operations in closely spaced relationship as shown as 23a and 23b in FIG. 10, thereby defining kinks at 23a at either side of each head.

While the system illustrated in FIGS. 1 allows the formation of a double-chain stitch above the coil, we prefer the system illustrated in FIGS. 14 and 15 because this arrangement conceals and masks the attachment thread and eliminates the need for a separate filler cord. Using basically the retainers 4, 5 of FIG. 1, the apparatus comprises a loop former L which engages the thread loop 21 as the needle N is withdrawn. The loop 21 is then stretched only across the lower shank a of the synthetic-resin filament 13 while the upper shank 25b conceals the row of stitching generally represented at 22. Here, a single-thread chain stitch is employed. Rollers as shown at 24 and 24a serve to compress the shanks of the coupling element as indicated in FIG. 15 with ultrasonic welding via a source S to clamp the threads 21 at 25 and weld the shanks together at 250. Hence, even with breakage of the thread T, the chain stitch cannot pull out.

In FIG. 13, we have shown another arrangement especially designed for the application of the coupling element 114 to a large-area fabric 120 along a hemmed edge 120a. In this case, the lever arm 103 with its arm 111 is mounted on a shaft 109 for swinging movement as previously described to carry the filament 113 to the stitching location through the eye 112. Here, however, the caliper is open in the direction of the fabric edge and the fabric does not impede the motion of the swinging lever. The finger 150 and the retainers 104, 105 are shown with their respective operating levers.

It will be apparent that the rollers 24 and 24a illustrated in FIG. 15 can be used wherever a thermal bond or clamping operation is desired in the system of the present invention and will be constituted as a sonotrode or anvil respectively. Furthermore, the threads 21 of the row 22 can be affixed to the shanks by adhesive or cement, if desired.

The improvement described and illustrated is believed to admit of many modifications within the ability of persons skilled in the art, all such modifications being considered within the spirit and scope of the invention except as limited by the appended claims.

We claim:

1. A-method of making a slide-fastener-stringer half, comprising the steps of:

a. advancing a flat stitchable support past a stitching location;

feeding a synthetic resin filament onto a surface of said support;

0. stitching through said support to flank the stretch of synthetic resin filament fed to said support between a pair of stitch-forming thread portions;

. bending said filament to form a loop rising above said support and upstanding therefrom;

e. feeding said filament above said support substantially parallel to said stretch;

f. bending said filament in a further loop to deposit a second stretch spaced along said support from said first stretch;

g. stitching through said support to anchor said second stretch thereto with thread portions on either side thereof; and

h. similarly repeating steps (b) through (f) to form a substantially continuous coupling-element coil along an edge of said support with turns'formed by each stretch and the bends connected thereto.

2. A method defined in claim 1, further comprising the step of deforming said filament at spaced-apart,locations corresponding to the bends formed along one side of said coupling element to produce respective heads therein, said deforming of said filament being effective in the cadence of bending thereof.

3. The method defined in claim 2 wherein the portion of each turn lying above the respective stretch is anchored between the thread portions flanking the stretch upon each stitching through of said portion, said stitching through of said portion being constituted by a chain stitch.

4. A method of making a slide-fastener-stringer half, comprising the steps of: g

a. advancing a flat stitchable support past a stitching locationz b. feeding a synthetic resin filament onto a surface of said support;

c. stitching through said support to flank the stretch of synthetic resin filament fed to said support between a pair of stitch-forming thread portions;

(1. bending said filament to form a loop rising above said support and upstanding therefrom;

e. feeding said filament above said support substan tially parallel to said stretch;

f. bending said filament in a further loop to deposit a second stretch spaced along said support from said first stretch;

g. deforming said filament at spaced-apart locations corresponding-to alternate bends whereby, upon .bending, the deformed locations of said filament produce lateral protrusions forming heads;

h. stitching through said support to anchor said second stretch thereto with thread portions on either side thereof;

i. feeding a synthetic resin filament onto a surface of said support;

j. stitching through said support to flank the stretch of synthetic resin filament fed to said support between a pair of stitch-forming thread portions;

k. bending said filament to form a loop rising above said support and upstanding therefrom;

l. feeding said filament above said support substantially parallel to said stretch;

m. bending said filament in a further loop to deposit a second stretch spaced along said support from said first stretch; and

n. deforming said filament at spaced-apart locations corresponding to alternate bends whereby, upon bending, the deformed locations of said filament produce lateral protrusions forming heads. 

1. A method of making a slide-fastener-stringer half, comprising the steps of: a. advancing a flat stitchable support past a stitching location; b. feeding a synthetic resin filament onto a surface of said support; c. stitching through said support to flank the stretch of synthetic resin filament fed to said support between a pair of stitch-forming thread portions; d. bending said filament to form a loop rising above said support and upstanding therefrom; e. feeding said filament above said support substantially parallel to said stretch; f. bending said filament in a further loop to deposit a second stretch spaced along said support from said first stretch; g. stitching through said support to anchor said second stretch thereto with thread portions on either side thereOf; and h. similarly repeating steps (b) through (f) to form a substantially continuous coupling-element coil along an edge of said support with turns formed by each stretch and the bends connected thereto.
 2. A method defined in claim 1, further comprising the step of deforming said filament at spaced-apart locations corresponding to the bends formed along one side of said coupling element to produce respective heads therein, said deforming of said filament being effective in the cadence of bending thereof.
 3. The method defined in claim 2 wherein the portion of each turn lying above the respective stretch is anchored between the thread portions flanking the stretch upon each stitching through of said portion, said stitching through of said portion being constituted by a chain stitch.
 4. A method of making a slide-fastener-stringer half, comprising the steps of: a. advancing a flat stitchable support past a stitching location: b. feeding a synthetic resin filament onto a surface of said support; c. stitching through said support to flank the stretch of synthetic resin filament fed to said support between a pair of stitch-forming thread portions; d. bending said filament to form a loop rising above said support and upstanding therefrom; e. feeding said filament above said support substantially parallel to said stretch; f. bending said filament in a further loop to deposit a second stretch spaced along said support from said first stretch; g. deforming said filament at spaced-apart locations corresponding to alternate bends whereby, upon bending, the deformed locations of said filament produce lateral protrusions forming heads; h. stitching through said support to anchor said second stretch thereto with thread portions on either side thereof; i. feeding a synthetic resin filament onto a surface of said support; j. stitching through said support to flank the stretch of synthetic resin filament fed to said support between a pair of stitch-forming thread portions; k. bending said filament to form a loop rising above said support and upstanding therefrom; l. feeding said filament above said support substantially parallel to said stretch; m. bending said filament in a further loop to deposit a second stretch spaced along said support from said first stretch; and n. deforming said filament at spaced-apart locations corresponding to alternate bends whereby, upon bending, the deformed locations of said filament produce lateral protrusions forming heads. 